Need help with pe90 470 conversion

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Z.Brown
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Joined: Mon Jan 04, 2021 8:18 pm

Need help with pe90 470 conversion

Post by Z.Brown »

I have a pe90 with 470 jugs and a holley demon 2 barrel, motor runs fine if you ease into the throttle but if you got to accelerate it stumbles and sometimes backfires, and it has an inconsistent misfire at WOT any help is appreciated

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John Fenner
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Location: Miami(Cuba) Fl.

Re: Need help with pe90 470 conversion

Post by John Fenner »

First off, is the accelerator pump adjusted correctly, is there fuel coming out of squirters, have there been any plug color checks to see what the mixture is? What pistons are in it, (compression ratio) ignition timing?
I never finish anyth,,,.

Z.Brown
Southern Airboat Member
Posts: 6
Joined: Mon Jan 04, 2021 8:18 pm

Re: Need help with pe90 470 conversion

Post by Z.Brown »

Have fuel out of the squirters never messed with the accelerator pump, I haven't checked the plugs yet I'm checking them today, I have a feeling they're going to look pretty lean

Z.Brown
Southern Airboat Member
Posts: 6
Joined: Mon Jan 04, 2021 8:18 pm

Re: Need help with pe90 470 conversion

Post by Z.Brown »

Pulled all the plugs they all look pretty good,
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BobBrack
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Joined: Thu May 22, 2008 8:12 pm

Re: Need help with pe90 470 conversion

Post by BobBrack »

They are both leaner than I like to see them. What size jets are in the carb? I would also look for an intake leak as well.

Z.Brown
Southern Airboat Member
Posts: 6
Joined: Mon Jan 04, 2021 8:18 pm

Re: Need help with pe90 470 conversion

Post by Z.Brown »

I honestly couldn't tell you I've never messed with them, I do think the squirter is a little small its only a .031, also what's a good size jet to run?

BobBrack
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Joined: Thu May 22, 2008 8:12 pm

Re: Need help with pe90 470 conversion

Post by BobBrack »

Ive only ran the holly 500 with the setup that you have. If my memory serves me correctly I had #72 jets in it. Im not sure about how the Demon carb works.

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John Fenner
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Joined: Tue Feb 14, 2012 12:26 pm
Location: Miami(Cuba) Fl.

Re: Need help with pe90 470 conversion

Post by John Fenner »

Bit on the lean side, not sure what Demons come with out of the box, 31 squirter is fine, order gaskets for the bowl and metering plate, order a power valve plug, order a pair each of # 74-75-76 jets.
Ok, that said be very sure that the accelerator arm has zero lash to the pump and cam and it squirts with very little movement of throttle arm.
Double check mag timing, TDC #1, back up the number of teeth on ring gear equal to starter pinion gear count, that will get you to 25° +/-
Remove sight plugs on mags, bevel tooth shall be in center of window, if not, they should be re timed, also depending on compression ratio, may need to drop it back to 22° if still stuttering on wide open throttle, go with one step at a time.
I never finish anyth,,,.

Z.Brown
Southern Airboat Member
Posts: 6
Joined: Mon Jan 04, 2021 8:18 pm

Re: Need help with pe90 470 conversion

Post by Z.Brown »

I appreciate the advice I'll get some parts together and take it slow

Z.Brown
Southern Airboat Member
Posts: 6
Joined: Mon Jan 04, 2021 8:18 pm

Re: Need help with pe90 470 conversion

Post by Z.Brown »

Ordered squirters, jets, and an accelerator pump its definitely running lean
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